Go Back  Bike Forums > Bike Forums > Road Cycling
Reload this Page >

Speed sensors

Road Cycling “It is by riding a bicycle that you learn the contours of a country best, since you have to sweat up the hills and coast down them. Thus you remember them as they actually are, while in a motor car only a high hill impresses you, and you have no such accurate remembrance of country you have driven through as you gain by riding a bicycle.” -- Ernest Hemingway

Speed sensors

Old 05-31-19, 09:40 PM
  #1  
bonsai171
Senior Member
Thread Starter
 
Join Date: Nov 2014
Posts: 890
Mentioned: 33 Post(s)
Tagged: 0 Thread(s)
Quoted: 445 Post(s)
Likes: 0
Liked 12 Times in 7 Posts
Speed sensors

Does anybody have 1 speed sensor they swap between multiple bikes? I have 3 bikes, trying to decide if I should get 3 speed sensors or just move around the one I have.

Dave
bonsai171 is offline  
Old 05-31-19, 09:53 PM
  #2  
jadocs
Senior Member
 
jadocs's Avatar
 
Join Date: Jul 2018
Location: USA
Posts: 723

Bikes: Litespeed T2 Disc, Fondirest P4 Carbon, Fuji Cross 2.0, Specialized Fatboy

Mentioned: 10 Post(s)
Tagged: 0 Thread(s)
Quoted: 301 Post(s)
Liked 55 Times in 42 Posts
What kind of speed sensor are you talking about? Bluetooth?, magnetic?
jadocs is offline  
Old 05-31-19, 10:27 PM
  #3  
Seattle Forrest
Senior Member
 
Seattle Forrest's Avatar
 
Join Date: Mar 2010
Location: Seattle, WA
Posts: 19,082
Mentioned: 43 Post(s)
Tagged: 0 Thread(s)
Quoted: 7978 Post(s)
Liked 190 Times in 124 Posts
I have a GPS speed sensor I used on my bike, skis, and on rental bikes. A wheel or hub magnet seems like it would be tedious to move around.
Seattle Forrest is offline  
Old 06-01-19, 12:44 AM
  #4  
bonsai171
Senior Member
Thread Starter
 
Join Date: Nov 2014
Posts: 890
Mentioned: 33 Post(s)
Tagged: 0 Thread(s)
Quoted: 445 Post(s)
Likes: 0
Liked 12 Times in 7 Posts
It is the Wahoo speed sensor. It wraps around the front or rear hub with a thick band that stretches. It is Ant + and Bluetooth.
bonsai171 is offline  
Old 06-01-19, 04:33 AM
  #5  
GlennR
Formerly oldnslow2
 
GlennR's Avatar
 
Join Date: Nov 2011
Location: Long Island, New York, USA
Posts: 5,409

Bikes: Trek Emonda SLR, Sram eTap, Zipp 303

Mentioned: 24 Post(s)
Tagged: 0 Thread(s)
Quoted: 1108 Post(s)
Liked 90 Times in 51 Posts
Garmins are GPS so you don't need a speed sensor.
GlennR is offline  
Old 06-01-19, 06:56 AM
  #6  
bonsai171
Senior Member
Thread Starter
 
Join Date: Nov 2014
Posts: 890
Mentioned: 33 Post(s)
Tagged: 0 Thread(s)
Quoted: 445 Post(s)
Likes: 0
Liked 12 Times in 7 Posts
Originally Posted by oldnslow2 View Post
Garmins are GPS so you don't need a speed sensor.
I'm actually using a Wahoo Elemnt Bolt. Right now 1 bike has the external sensor, the other two don't. We have a 95 mile bike trail down here that I ride often, and there is heavy tree cover. In some areas the speed will fluctuate (will be riding a steady pace of 16 mph, then the speed will drop down to 10 or 0 then go back up). Works better on the bike with the external speed sensor. I suspect the same will happen while mountain biking (had some dropouts riding gravel thru areas with heavy trees last weekend without an external sensor too).

Dave
bonsai171 is offline  
Old 06-01-19, 07:13 AM
  #7  
GlennR
Formerly oldnslow2
 
GlennR's Avatar
 
Join Date: Nov 2011
Location: Long Island, New York, USA
Posts: 5,409

Bikes: Trek Emonda SLR, Sram eTap, Zipp 303

Mentioned: 24 Post(s)
Tagged: 0 Thread(s)
Quoted: 1108 Post(s)
Liked 90 Times in 51 Posts
So unless you're training or a "Strava nut" does it really matter?

If it does then does moving the sensor from bike to bike more trouble than buying 2 more sensors?

I have 2 bikes and the Garmin supports multiple bike profiles. On my road bike i have a single sensor that does both cadence and speed. On my CX bike I only have a cadence sensor and speed is via GPS. I never noticed any inconsistent speed issues.
GlennR is offline  
Old 06-01-19, 08:54 AM
  #8  
Robert A
Senior Member
 
Join Date: Sep 2012
Location: Los Angeles
Posts: 398

Bikes: 2019 CAAD12, 2015 Specialized Sirrus Comp

Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 280 Post(s)
Likes: 0
Liked 2 Times in 2 Posts
I'm sorry, I don't understand your objective. I have the same Bolt/sensor combination as you. You can swap sensors between bikes, or rely on GPS for the two bikes that don't have the sensor. Keep in mind that each time you swap, your Bolt has to recalibrate for differing wheel sizes (assuming you're on auto-calibrate) and this might lead to measurement errors until the calibration is complete.

Originally Posted by bonsai171 View Post
I'm actually using a Wahoo Elemnt Bolt. Right now 1 bike has the external sensor, the other two don't. We have a 95 mile bike trail down here that I ride often, and there is heavy tree cover. In some areas the speed will fluctuate (will be riding a steady pace of 16 mph, then the speed will drop down to 10 or 0 then go back up). Works better on the bike with the external speed sensor. I suspect the same will happen while mountain biking (had some dropouts riding gravel thru areas with heavy trees last weekend without an external sensor too).

Dave
Robert A is offline  
Old 06-01-19, 10:42 AM
  #9  
bonsai171
Senior Member
Thread Starter
 
Join Date: Nov 2014
Posts: 890
Mentioned: 33 Post(s)
Tagged: 0 Thread(s)
Quoted: 445 Post(s)
Likes: 0
Liked 12 Times in 7 Posts
Originally Posted by Robert A View Post
I'm sorry, I don't understand your objective. I have the same Bolt/sensor combination as you. You can swap sensors between bikes, or rely on GPS for the two bikes that don't have the sensor. Keep in mind that each time you swap, your Bolt has to recalibrate for differing wheel sizes (assuming you're on auto-calibrate) and this might lead to measurement errors until the calibration is complete.
That was helpful. I was hoping to avoid buying 2 more external sensors at $40 each, but it sounds like it might make sense to do eventually for my situation.

Dave
bonsai171 is offline  
Old 06-01-19, 10:48 AM
  #10  
daoswald
Senior Member
 
Join Date: Apr 2008
Location: Salt Lake City, UT (Formerly Los Angeles, CA)
Posts: 1,025

Bikes: 2008 Cannondale Synapse -- 2014 Cannondale Quick CX

Mentioned: 4 Post(s)
Tagged: 0 Thread(s)
Quoted: 175 Post(s)
Likes: 0
Liked 26 Times in 14 Posts
On my road bike I have speed and cadence sensors for my Garmin Edge 820. On my hybrid/commuter I do not. I do move the GPS from bike to bike, but I don't move the sensors: The cadence sensor is too hard to unmount and remount to do it frequently. The speed sensor is easier, but would require that the GPS recalibrate each time.

I considered getting a set of sensors for the hybrid/commuter but two problems: One, sometimes my brother borrows the hybrid to ride with me. My GPS would pick up both sensors whenever we're within fifteen feet of each other, and that would be really annoying. The other reason is... who cares. It's a hybrid/commuter. I do my fitness training on the road bike.
daoswald is offline  
Old 06-01-19, 12:47 PM
  #11  
Steve B.
Senior Member
 
Join Date: Jul 2007
Location: South shore, L.I., NY
Posts: 3,237

Bikes: Flyxii FR322, Soma Smoothie, Miyata City Liner, Specialized FSR Comp, Fuji Professional

Mentioned: 11 Post(s)
Tagged: 0 Thread(s)
Quoted: 1082 Post(s)
Liked 24 Times in 17 Posts
I use a Garmin 1000 on 5 different bikes. I have a speed sensor on my plastic road bike, as I often ride in a group where being able to maintain a constant and steady speed is important. A speed sensor in that scenario lends to more accurate speed indication when using a GPS only has a lag as to the current speed. I also use speed sensors on my mt. bikes, as riding in heavily wooded area's or when riding on trails that have a lot of tight and twisty turns, lends to a more accurate distance track. I do not have or need sensors on the 2 bikes I use for commuting.
Steve B. is offline  
Old 06-01-19, 01:51 PM
  #12  
WhyFi
Senior Member
 
WhyFi's Avatar
 
Join Date: Jan 2010
Location: Got a castle in - er, Minneapolis, that's where I dwell!
Posts: 24,842

Bikes: 2016 Diamondback Haanjo, 2018 Trek Domane SL5 Gravel

Mentioned: 298 Post(s)
Tagged: 1 Thread(s)
Quoted: 8884 Post(s)
Liked 135 Times in 81 Posts
Originally Posted by oldnslow2 View Post
So unless you're training or a "Strava nut" does it really matter?
Actually, if you're a "Strava nut" it's completely irrelevant. Strava disregards speed sensor info and only goes off of GPS, so the sensors would only be for the benefit of the Bolt.
WhyFi is offline  
Old 06-01-19, 01:53 PM
  #13  
GlennR
Formerly oldnslow2
 
GlennR's Avatar
 
Join Date: Nov 2011
Location: Long Island, New York, USA
Posts: 5,409

Bikes: Trek Emonda SLR, Sram eTap, Zipp 303

Mentioned: 24 Post(s)
Tagged: 0 Thread(s)
Quoted: 1108 Post(s)
Liked 90 Times in 51 Posts
Originally Posted by WhyFi View Post
Actually, if you're a "Strava nut" it's completely irrelevant. Strava disregards speed sensor info and only goes off of GPS, so the sensors would only be for the benefit of the Bolt.
Didn't know that.
GlennR is offline  
Old 06-01-19, 04:37 PM
  #14  
TrojanHorse
SuperGimp
 
TrojanHorse's Avatar
 
Join Date: Mar 2010
Location: Whittier, CA
Posts: 13,138

Bikes: Specialized Roubaix

Mentioned: 134 Post(s)
Tagged: 0 Thread(s)
Quoted: 1008 Post(s)
Liked 23 Times in 18 Posts
Originally Posted by WhyFi View Post
Actually, if you're a "Strava nut" it's completely irrelevant. Strava disregards speed sensor info and only goes off of GPS, so the sensors would only be for the benefit of the Bolt.
Yep - I gave up on them a while ago for precisely that reason. It smooths out your speed display on your head unit. Big whoop.
TrojanHorse is offline  
Old 06-01-19, 09:53 PM
  #15  
bonsai171
Senior Member
Thread Starter
 
Join Date: Nov 2014
Posts: 890
Mentioned: 33 Post(s)
Tagged: 0 Thread(s)
Quoted: 445 Post(s)
Likes: 0
Liked 12 Times in 7 Posts
Originally Posted by TrojanHorse View Post
Yep - I gave up on them a while ago for precisely that reason. It smooths out your speed display on your head unit. Big whoop.
Sounds like $80 saved for me if the Elemnt bolt works well on mtb trails!

Thanks everyone.

Dave
bonsai171 is offline  
Old 06-01-19, 11:01 PM
  #16  
Seattle Forrest
Senior Member
 
Seattle Forrest's Avatar
 
Join Date: Mar 2010
Location: Seattle, WA
Posts: 19,082
Mentioned: 43 Post(s)
Tagged: 0 Thread(s)
Quoted: 7978 Post(s)
Liked 190 Times in 124 Posts
Originally Posted by WhyFi View Post
Actually, if you're a "Strava nut" it's completely irrelevant. Strava disregards speed sensor info and only goes off of GPS, so the sensors would only be for the benefit of the Bolt.
That's interesting. I guess if you think about it, be they need the GPS data to figure out when you came into the segment and when you left.
Seattle Forrest is offline  
Old 06-01-19, 11:06 PM
  #17  
Robert A
Senior Member
 
Join Date: Sep 2012
Location: Los Angeles
Posts: 398

Bikes: 2019 CAAD12, 2015 Specialized Sirrus Comp

Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 280 Post(s)
Likes: 0
Liked 2 Times in 2 Posts
Originally Posted by WhyFi View Post
Actually, if you're a "Strava nut" it's completely irrelevant. Strava disregards speed sensor info and only goes off of GPS, so the sensors would only be for the benefit of the Bolt.
My Bolt gets data from my speed sensor and uploads the ride directly to Strava. The resulting data on Strava and my Bolt are 100% identical, so Strava IS pulling speed sensor data, at least in my setup.
Robert A is offline  
Old 06-02-19, 05:13 AM
  #18  
WhyFi
Senior Member
 
WhyFi's Avatar
 
Join Date: Jan 2010
Location: Got a castle in - er, Minneapolis, that's where I dwell!
Posts: 24,842

Bikes: 2016 Diamondback Haanjo, 2018 Trek Domane SL5 Gravel

Mentioned: 298 Post(s)
Tagged: 1 Thread(s)
Quoted: 8884 Post(s)
Liked 135 Times in 81 Posts
Originally Posted by Robert A View Post
My Bolt gets data from my speed sensor and uploads the ride directly to Strava. The resulting data on Strava and my Bolt are 100% identical, so Strava IS pulling speed sensor data, at least in my setup.
You're right - looks like I misspoke. Strava segments disregards speed sensors, but it looks like I was wrong in thinking that they were completely disregarded.

Then again, KOMs and PRs are *everything*, so really... I'm still right.
WhyFi is offline  
Old 06-02-19, 06:02 AM
  #19  
Hiro11
Senior Member
 
Join Date: Jun 2010
Posts: 2,056

Bikes: To the right: opinions, not facts.

Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 447 Post(s)
Likes: 0
Liked 22 Times in 14 Posts
I personally don't see the need for speed sensors with a GPS head unit. The average speed results I get off of GPS are very consistent with those from people I ride with who have speed sensors. I get that there's a lag while accelerating / decelerating but this appears to work itself out over time. Instantaneous speed doesn't seem very important to me, especially given that I have instantaneous power and instantaneous heart displayed on my head unit, both of which are better measures of effort. Regardless, the speed updates in a second or so.
Hiro11 is offline  
Old 06-02-19, 06:40 AM
  #20  
Marcus_Ti 
Frozen Solid.
 
Marcus_Ti's Avatar
 
Join Date: Sep 2014
Location: Lincoln, Nebraska
Posts: 4,672

Bikes: Roadie: Seven Axiom Race Ti w/Chorus 11s. CX/Adventure: Carver Gravel Grinder w/ Di2

Mentioned: 27 Post(s)
Tagged: 0 Thread(s)
Quoted: 1923 Post(s)
Liked 56 Times in 36 Posts
Originally Posted by Hiro11 View Post
I personally don't see the need for speed sensors with a GPS head unit. The average speed results I get off of GPS are very consistent with those from people I ride with who have speed sensors. I get that there's a lag while accelerating / decelerating but this appears to work itself out over time. Instantaneous speed doesn't seem very important to me, especially given that I have instantaneous power and instantaneous heart displayed on my head unit, both of which are better measures of effort. Regardless, the speed updates in a second or so.
There's also the other added bonus. Better battery life.
Marcus_Ti is offline  
Old 06-02-19, 06:52 AM
  #21  
GlennR
Formerly oldnslow2
 
GlennR's Avatar
 
Join Date: Nov 2011
Location: Long Island, New York, USA
Posts: 5,409

Bikes: Trek Emonda SLR, Sram eTap, Zipp 303

Mentioned: 24 Post(s)
Tagged: 0 Thread(s)
Quoted: 1108 Post(s)
Liked 90 Times in 51 Posts
Originally Posted by Hiro11 View Post
instantaneous heart displayed
Actually the your heart rate lags as it takes a minute for your heart to get up to speed when you start to climb and a few minutes for it to come back when when you reach the top.
GlennR is offline  
Old 06-02-19, 05:41 PM
  #22  
Robert A
Senior Member
 
Join Date: Sep 2012
Location: Los Angeles
Posts: 398

Bikes: 2019 CAAD12, 2015 Specialized Sirrus Comp

Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 280 Post(s)
Likes: 0
Liked 2 Times in 2 Posts
Originally Posted by Hiro11 View Post
I personally don't see the need for speed sensors with a GPS head unit. The average speed results I get off of GPS are very consistent with those from people I ride with who have speed sensors. I get that there's a lag while accelerating / decelerating but this appears to work itself out over time. Instantaneous speed doesn't seem very important to me, especially given that I have instantaneous power and instantaneous heart displayed on my head unit, both of which are better measures of effort. Regardless, the speed updates in a second or so.
I tend to agree, and I probably wouldn't have bought one were it not for the HR and cadence sensors that came together in the package.
Robert A is offline  
Old 06-02-19, 08:22 PM
  #23  
sdmc530
Heft On Wheels
 
sdmc530's Avatar
 
Join Date: Nov 2014
Location: South Dakota
Posts: 1,991

Bikes: Specialized,Cannondale

Mentioned: 8 Post(s)
Tagged: 0 Thread(s)
Quoted: 536 Post(s)
Liked 63 Times in 50 Posts
I have a speed sensor on one bike, haven't seemed the need to put in on the others. I probably wouldn't buy another one either. Its nice when the GPS gets wanky from time to time but that is pretty rare anymore. Its more accurate but how accurate do you really need to be on the speed?

Power I want accurate, speed if its off just a touch, I am alright with that.
sdmc530 is offline  
Old 06-03-19, 07:08 AM
  #24  
jadocs
Senior Member
 
jadocs's Avatar
 
Join Date: Jul 2018
Location: USA
Posts: 723

Bikes: Litespeed T2 Disc, Fondirest P4 Carbon, Fuji Cross 2.0, Specialized Fatboy

Mentioned: 10 Post(s)
Tagged: 0 Thread(s)
Quoted: 301 Post(s)
Liked 55 Times in 42 Posts
Originally Posted by Robert A View Post
My Bolt gets data from my speed sensor and uploads the ride directly to Strava. The resulting data on Strava and my Bolt are 100% identical, so Strava IS pulling speed sensor data, at least in my setup.
Mine does too, however I have noticed on a few rides that have uploaded, that the average speed in Strava has been .1 mph on the low side. Example, sometimes a 20mph average on the Bolt with a speed sensor shows up in Strava as 19.9 mph. Not sure what is going on there.
jadocs is offline  
Old 06-03-19, 08:34 AM
  #25  
WhyFi
Senior Member
 
WhyFi's Avatar
 
Join Date: Jan 2010
Location: Got a castle in - er, Minneapolis, that's where I dwell!
Posts: 24,842

Bikes: 2016 Diamondback Haanjo, 2018 Trek Domane SL5 Gravel

Mentioned: 298 Post(s)
Tagged: 1 Thread(s)
Quoted: 8884 Post(s)
Liked 135 Times in 81 Posts
Originally Posted by jadocs View Post
Mine does too, however I have noticed on a few rides that have uploaded, that the average speed in Strava has been .1 mph on the low side. Example, sometimes a 20mph average on the Bolt with a speed sensor shows up in Strava as 19.9 mph. Not sure what is going on there.
The most likely cause is that Strava and your Bolt have different thresholds for what they consider to be moving, so average moving speeds will sometimes be different between the two.
WhyFi is offline  

Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

Copyright © 2018 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.